Field of the Invention
The present invention relates to an image forming apparatus, and more specifically, an image forming apparatus that a developing unit having a developing roller is made insertable or extractable in a longitudinal direction to or from a developing unit attaching portion provided in an apparatus main body.
Description of the Related Art
Conventionally, an image forming apparatus that a photoreceptor unit comprising a photoreceptor drum (electrostatic latent image bearing member) and a developing unit having a developing roller are individually insertable or extractable to or from an apparatus main body is known. In such an image forming apparatus, it is necessary to bring the photoreceptor drum and the developing roller close to each other at the time of image forming, whereas it is necessary to guide the developing unit so as to be moved on a position departed from the photoreceptor drum at the time of inserting the developing unit into an apparatus main body in order to prevent the developing unit from being brought into contact to the photoreceptor drum and thus damaging the photoreceptor drum. In the conventional image forming apparatus, when arranging the developing roller in a position close to the horizontal direction with respect to the photoreceptor drum, the photoreceptor drum and the developing unit are made to be separated from each other by performing parallel moving of the developing unit to an approximately horizontal direction from a normal position. However, this requires a large space in the horizontal direction in order to ensure a space between the developing unit and the photoreceptor drum, there is a problem that the apparatus main body becomes large.
On the other hand, there is disclosed in Japanese patent application laying-open No. 2015-82056 [G03G 15/18, G03G 21/00, G03G 15/00] (patent literature 1) an image forming apparatus comprising a developing unit movable around a rocking shaft between a contacting position and a separated position with respect to a photoreceptor unit in a state where the developing unit is attached to an apparatus main body. In the image forming apparatus of the patent literature 1, the developing unit is made a state where the developing unit is inclined so as to be separated from the photoreceptor drum at the time of insertion of the developing unit into the apparatus main body. Then, by turning a control lever after completion of the insertion of the developing unit, a turning mechanism of the developing unit is operated, thereby bringing the developing unit into contact with the photoreceptor drum.
However, in the image forming apparatus of the patent literature 1, in order to turn the developing unit with using the turning mechanism interlocked with the control lever, it requires a number of components and a cost. Furthermore, since it is necessary to perform separately an operation of inserting the developing unit into the apparatus main body and an operation of turning the developing unit after completion of insertion, an operation burden on a user increases.